1. Field of the Invention
The present invention relates to an air conditioner. More particularly, the present invention relates to a control system for controlling an electric compressor of the air conditioner.
2. Description of Related Art
In an air conditioner disclosed in JP-A-2001-26214, a control target rotation speed fn of a compressor is determined as follows. That is, an actual cooling capacity TE (e.g., air temperature immediately after an evaporator) generated in an interior heat exchanger is detected, a target cooling capacity TEO of the interior heat exchanger is determined, and a difference ΔTE between the TE and the TEO is calculated. Then, an incremental rotation speed Δf with respect to a present rotation speed fn−1 is determined based on the difference ΔTE, and the control target rotation speed fn is determined by adding the incremental rotation speed Δf to the present rotation speed fn−1.
In a feedback control of the air conditioner according to JP-A-2001-26214, the control target rotation speed fn converges in a stable speed range in any heat load condition. Therefore, an excessive value of the incremental rotation speed Δf cannot be set.
Generally, a rotation speed of the compressor changes larger than the incremental rotation speed Δf determined as described above, for example, when the compressor is started. In this case, according to the above feedback control, the control target rotation speed fn is obtained by adding the incremental rotation speed Δf to the present rotation speed fn−1, that is, 0 rpm. Therefore, the excessive value of the incremental rotation speed Δf cannot be set as described above. Accordingly, it takes a long time to increase the rotation speed of the compressor to a necessary speed. Thus, the cooling capacity generated in the interior heat exchanger increases slowly and a sufficient cooling capacity may not be obtained, for example, in a quick cooling operation immediately after starting of the compressor.